Color photography



March 13, ,1934. E. AA. WEAVER coLoR- PHOTOGRAEHY Filed Jan. 31, i930'Duns/01h..

S7/mrt l ,gym Mmm/v Ins' Wibrfeys Patented Mnl'. 13, 1934` PATENT OFFICE1,951,043 coma Pno'r'ooasrnr Eastman A. Weaver, Winchester, Mass.,assignor,

meane assignments, to Technicolor, .Inc.,

New York, N. Y., a corporation of Delaware Application January 31, 1930,Serial No. 425,013

This invention relates to composite photographic fllm comprising aplurality of separable iilms, and is particularly applicable to motionpicture nlm provided with a plurality of emulsions adapted to recordsuperposed images for use in producing colored pictures.

One of the objects of this invention is to provide a composite nlmcomprising a pair of iilms with their emulsion sides placed face to faceand Joined by adhesive' which does not itself cause any appreciabledispersion of light, butv which serves to exclude air from between theemulsions and thus prevents the refraction caused by presence of airbetween adjacent separately-supported emulsions.

Another object is to provide a composite film of this kind which mayreadily be separated into its constituent films by rupture of theadhesive without damage to the emulsions, and preferably without thenecessityfor treatment of the adhesive preparatory to such separation.

' separation.

A further object is to provide composite rllms of 'this kind in whichthe adhesive may be readily removed upon separation of the iilm and toprovide improved ways of removing the adhesive.

My invention includes also an improved art of making photographicnegatives 4.and has for an object to. provide a way of adhesivelyjoining two or more elements of a composite film for perforation,winding. exposure, or storage, whereby the lm may easily be separatedfor develop-l ment` without the necessity of treating the nlm withchemicals which are injurious to the celluloid supports of the film, orof prolonged soaking .of thecomposite iilm with waterpreparatory toOther objects of my invention will be apparent from the followingexplanation and from the accompanying drawing which illustrates,diagrammatically and by way of example, two-photographie illms madeaccording to my invention.

Fig. l'is a. side view of a composite'photographic nlm produced withthree emulsions; --and Fig. 2 is a similar view of acompositephotographic film provided withtwo emulsions.

The composite photographic illm of li'ig. 1

comprises two supports 11 and 12 ziftransparent, flexible, relativelystrong material, such as celluloid, which serve to carry light sensitiveemulsions 13, 14l and 16, emulsion 13 being firmly aillxed to.suppo:'t11, and emulsions 14 and 16 being iirmly afilxed `to support 12.

These emulsions differ in sensitiveness to certain colors, and apreferable arrangement is to utilize an emulsion 16 which is relativelyinsensitive to green and red wave lengths and preferably chieflysensitive to blue and violet wave lengths, an emulsionA 14 relativelyinsensitive to red wavelengths and preferably chiefly sensitive to greenwave lengths, and an emulsion 13 sensitive to red wave lengths.Thecelluloicl support 12 and its two emulsions 14 and 16 constitute oneseparable film, while the celluloid support l1 and its attached emulsion13 .constitute another .separable film. These two separable lms areunited by adhesive 15 to hold them together during simultaneous exposureoftheir emulsions to light. In Ithe drawing the arrow shows thedirection of the light. An image will be recorded by the blueA andviolet components of the 70 light in emulsion 16, an image will beformed by 4the green components of the light in emulsion 14,

-wave lengths may be prevented from aifecting the red record emulsion 13byproviding a red color filter incorporated in the entrant side ofemulsion 13, in the emergent side of emulsion 14, or in both.

Such color illters are not always indispensible. however, since byutilizing emulsions which are strongly absorptive of predeterminedspectral ranges of light, (usually those which form an n image therein)the emulsions themselves may be.` caused to screen from the underlyingemulsions these predetermined spectral ranges of light.

While the above described arrangement of emulsions is deemeddesirabieone'wof the lthree emulsions may be dispensed with.` Such aconstruction is illustrated in Fig. 2 of the drawing, in which emulsion16 is omitted, and the emulsion 14 attached directly to" the celluloidsupport 12. In of this form of composite nlm, images lol made uprespectively ofthe'A red and green components areobtained, and the blueviolet image 5s either omitted or, if desired, may be formed separatelyon another nlm.

The surfaces of photographic emulsions are 106 sion sidestogether, causerefraction of the light` passing from one emulsion to the other. Inunit- 110 ing the two illms which comprise my composite nlm I prefer toutilize an adhesive 15, preferably of similar refractive index to theemuls'ons, which serves to lill up the minute indentations of thesurfaces of the emulsions and thus minimize the refraction, but whichdoes not substantially separate the two adjacent emulsions nor addsubstant'ally to the thickness of the composite film. By'the use of anadhesive of this character, the

diifusion of the light passing throughthe emul- -'application to theillms will remain in a soft,

easily ruptured condition.

I have found that the sticking together of two films with their emulsionsides face to face is facilitated if the adhesive contains anappreciable amount 'of water. It seems probable that the water contanedin the adhesive serves to wet the surfaces of the adjacent emulsions andbrings into play the adhesive properties of the -gelatine itself.

If emulsions are united by being rolled forcibly into contactafterapplication of pure water, they are likely to unite fully andpermanently. I therefore prov=de with the water a substance preferablynon-adhesive or only slightly adhesive by itself for preventing suchcomplete and permanent union of the emulsions and reducing the adhesionto a mild and temporary degree adeouate to-hold the lms together duringperforav tion, rewinding, storage, exposure, etc., but insunlcient tohinder unduly their later separation when desired. I prefer to employa'substance which is transparent, in thin layers,fwhich is adapted toretain water and is miscible there-- with and which is non-volatile andnon-solidifyingv or slowly solidifying, and have "found that glycerineis suitable for this use. One example of a suitable composition ofthe'adhesive com- `Drses40 parts of water'and 60 parts of glycerine.

Further to reduce the relative water-content of the adhesive and.regulate its adhesive power, a

lsmall amount of a substance having in itself adhesive properties, suchfor example as glucose may be added. Such adhesive mixture or solutionis capable of remaining in a vscous or fluid condition. The adhssivesince viscous .or uid is naturally weaker than the emulsions andsupports of the lms, and the composite lm'thustemporarily joined mayeasily be separated withouty injury to the emulsions and withoutpreliminary treatment, such for example as soaking.A Vacuum probablyplays a part in such adhesion, 'as gelatine absorbswater with suchavidity as to produce actual suction if the supply is small, as itshould be to avoid swelling. y

In prepar'ng composite lm forI motion picture use, the separate supports11 and 12 each coated with their respective'emulsions may after theapplication ofthe adhesveto'one of 4the emulsions be brought togetherwith their emulsion sides in contact, pressed tightly together,preferably by, rolls, to insure good contactl and reduce the amount'ofadhesive between the emulsions, and if necessary wiped free from surplusadhesive. These operations may be performed rapidly, successively andcontinuously, and should be performed in darkness or in such degree ofillumination as will not affect the sensitive emulsions. When ready forvdevelopment the composite lm may be separated by being pulled apartthrough rupture of the adhesive, and after separation adhesive remainingon the emulsions may be washed or squeegeed off. The separated films maybe developed and vused in any desired manner in the productionof-colored pictures. The

through both of these'rimages, the more intense image then removed, anda second print taken through the remaining "image after rendering thelatter more intense, inthe manner described and claimed in Patent No.1,808,584 to Leonard T.

yTroland for Color photography, of May 7, 1931.

Instead of two saparate emulsions, these two images may beformed'in -asingle emulsion which has been supercially-color-sensitized.

The placing of the. emulsions 13 and 14 face to face with -nosubstantial separating body or diffusion-producinglayer or airspacetherebetween permits the vlight from the object photographed to formsharp images in both of these emulsions. The adhesion of. the two lmsduring handlingand exposure eliminates the chance of marking of theemulsions which may result from static, or frictional electricaldischarges caused by running twovemulsions together and separating themat relatively high speeds. In addition the sensitive emulsionsarevprotected from accidental scratching or abrasion.

I may obtain some of the above described advantages andcertainf otheradvantages by employing an adhesive which does not necessarily containwater but' which may be applied in such `a. manner asto rlll'thefminutesurface'indentations without substantiallyV separating the adjacentemulsions, whichmay easily be ruptured in separating the lms; and afterseparation may be removed mechanically.

Examples of Vsuch'an adhesive are rubber and transparent cementscontaining a gum, such as rubber, I prefer to apply such an adhesive intwo stages, by first applying a preliminary coat of a thin solution ofthe adhesive to the emulsion surfaces of the twojlms and then, afterdrying of lthe originally Huid-adhesive toy form a tackycoating-and'just as the lms areabout to pass between the unitingrollers, applying a solvent for the adhesive, with or without some ofthe adhesive agent in solution, preferably only over the picture areavof the lms. This method of applying the adhesive insures that the edgesof the films will be held firmly together, and permits the exclusion ofair from' between the picture areas. i

After exposure, the composite film may' be pulled apart through ruptureof-the adhesive, and the adhesive removed, 'if desired,` by passing theemulsion side of theseparated lm and adhering rubber adhesive intoandout of lrolling cony tact with a surface for which the adhesive has agreater affinity than :for the emulsion, for example, the surface of arotary member of tacky rubber. The adhesive on the nlm having moreafilnityfor the tacky rubber surface clings to this in passing, and isthus cleanly detached without injury to the emulsion.

Suitable solvents may if desired be employed for removing the adhesive,but I prefer the abovedescribed method of removal since it obviatesanydiihculty attendant upon Vthe remaining of sol'- vent with traces ofadhesive upon the surface of the emulsion.

From the foregoing itwill be evident that in one aspect a characteristicfeature of the invention consists in that the adhesive has less interna]strength than the emulsions have, so that there is no danger ofrupturlng the emulsions in the peeling process, and thereafter theadhive may be removed as aforesaid :without injury to the emulsions.

I claim:

l. Art of 'making photographic negative records which comprises joiningtwo photographic lms with emulsions face to face by means of a weakadhesive which fills the surface indentations of the emulsions withoutsubstantially separating the emulsions-exposing the combined iilm,separating the two nlms and removing the adhesive from the film. y

2.. Art of making photographic negative records which comprises joiningtwo Vphotographic films with emulsions face to face by means of a weakwater miscible adhesive which nils the surface indentations of theemulsions without substantially. separating the emulsions,- exposing thecombined nlm, ,separating the two films and removing the adhesive fromthe nlm.

- 3. A composite film adapted foruse in color photography comprising a.pair of films each coated with an emulsion, said iilms being superposedwith their emulsions face to face, the composits lm being providedbetween the adjacent emulsions with an easily separated adhesive whichfills the minute surface indentations of the adjacent emulsions withoutsubstantially separating the emulsions whereby refraction of lightpassing from one emulsion to the other is 'minimized.

4. A composite nlm adapted for use in color photography comprising apair of tllms each coated with an emulsion, said filmsbeing superposedwith their emulsions faceqto face, the composite `111m being providedbetween the adjacent emulsions with water soluble easily rupturedadhesive which lls the minute surface indentations of the adjacentemulsions without substantially separating the emulsions, wherebyrefraction of light passing from one emulsion to the other is minimized.Y

5. A composite film adapted for use in color photography comprising apair of lms each coated with an emulsion, said films being superposedwith emulsions face to face and the composite film being providedbetween the adjacent emulsions with easily ruptured adhesive offeringless resistance to splitting of thecomposite iilms than the otherelements thereof, whereby the superposed films may be pulled apart byrupt e of said adhesive without injury vto the emulsions, said adhesivebeing adapted to be removed from the emulsions mechanically withoutinjury to the,

emulsions.A Y

6'. Acomposite nlm adapted for in color photography comprising a pair offilms .each coated with an emulsion said films being super-d posed withtheir emulsions face to face, the composite nlm being provided betweenthe adjacent emulsionsowith adhesive including water and glycerine whichlls the minute surface indentations of the adjacent emulsions withoutsubstantially separating the emulsions, whereby refraction of lightpassing from one emulsion to the other '1. A composite iilm adapted foruse in color photography comprising a pair of films each coated with anemulsion. said films being superposed with their emulsions face to face,the composite film being provided between the adjacent emulsions witheasily ruptured adhesive including a gum which nils thef minute surfaceindentations of the adjacent emulsions without substantially separatingthe emulsions whereby refraction of light passing from one emulsion tothe other is minimized. Y

8. A composite lm adapted for use in color photography comprising a pairof films each coated with an emulsion, said films being superposed withtheir'emulsions face to face, the composite nlm being provided betweenthe adjacent emulsions with easily separated adhesive including rubberwhich4 fills the minute surface indentations of the adjacent emulsionswithout substantially separating the emulsions whereby refraction oflight passing from one emulsion to the other is minimized.

9. A composite nlm adapted for 4use in color photography comprising apair of films each oated with emulsion, said films being superposed withtheir emulsions face to face, the composite lm being provided betweenadjacent emulsions with adhesive including water and glycerne. 1n. Acomposite iilm adapted for-use in color photography comprising pair offilms each coated with an emulsion, said films being superposed withtheir emulsions face to face. the composite nlm provided betweenadjacent emulsions with adhesiveincluding rubber and offering lessresistance .to rupture than the other elements of the composite nlm. l

11. A composite .nlm adapted for use in color photography comprising apair of films each coated with an emulsion, said lms being superposedwith emulsion face to face and the composite iilm being provided betweenthe adjacent emulsions with normally soft easily ruptured adhesveoffering less resistance tosplitting ofthe composite film than the otherelements thereof, whereby the superposed iilms may be pulled apart bynipture of said adhesive without injury to the emulsions.

12. A composite film adapted for use in color photography comprising a.pair of lms each coated with. an emulsion, said lms being superposedwith emulsions face to face and the composite lm being provided betweenthe adjacent emulsions with normally soft easily ruptured adhesiveoffering less resistance to splitting of the composite films than. theother elements thereof, whereby the superposed films may-be pulled apartby rupture of said adhesive without injury to"the emulsions, saidadhesive being soluble in water, wherebyupon separation of the nlm saidadhesive may be removed from the emulsion by water.

13.. Art of removing an adhesive from the emulsion face ofa-photographic film without injury to theY emulsion which comprisesmoving the film into and out of contact with a tacky rubber surface forwhich the adhesive has a greater ailinity than :for the emulsion,whereby the adhesive clings to said surface and is detached from theemulsion.

14. Art of removing an adhesive containing a gum from the emulsion faceof a photographic lm without injury to the emulsion, which comprisesmoving the film into and out of contact with a surface substantiallyimmovable relative to said lm and for which the adhesive has a greateranity than for the emulsion, whereby the adhesive clings to said surfaceand is detached from the emulsion.

15. Art of making photographic negative records which comprises joiningtwo photographic lms with emulsions face to face by means of an adhesivewhich lls the surface indentations of

